Artificer s leveling-instrument



2 Sheets-Sheet 1.

(No Model.)

J. W. HARMON;

ARTIFIGERS LEVEL'ING INSTRUMENT.

No. 281,267. Patented July 17,1883;

N. PETERS. mwmm n lwr, washmgwn. a. c

(No Model.) I ZShets-Sheet 2.

v J. W. HA'RMON.

ARTIFIGBRS LEVELING INSTRUMENT. No. 281,267. Patented Jul lv, 1883 N.PETERS Phubuihogmpher. Wzuhmglan. D. c

Unrrnn STATES PATENT Orrrcn.

JOHN TV. HARMON, OF BOSTON, MASSACHUSETTS.

ARTIFlC ERS LEVELlNG-INSTRUMENT.

SPECIFICATION forming part of Letters Patent No. 281,267, dated July 17,1583. Application filed January 29, 1853. (No model.)

To all whom it may concern:

Be it known that I, JonN W'ARREN HAR- MON, of Boston, in the county ofSuffolk, of the Commonwealth 01" Massachusetts, have in vented a new anduseful Improvement in Artificers Leveling -Instruments; and I do herebydeclare the same to be described in the following specification andrepresented in the accompanying drawings, of which Figure 1 is a topview, Fig. 2 a front elevation, and Fig. 3 a transverse and mediansection, of an instrument provi tied with my invention, the nature ofwhich is defined in the claim hereinafter presented.

This instrument has a telescope, A, and an arched supporting-bar, B, towhich such telescope, at its middle, is pivoted, there being in the saidbar horizontal and vertical spirit levels Cand I). It also has screws EE for adjusting the axis of the telescope in parallelism with that ofthe horizontal spiritlevel. The bar B, at the center of its lower edge,is pivoted to a divided limb, G, at the center thereof, and such limb isfurnished with-three adjusting-screws, H, which screw into cars orprojections a, extending from thelimb at equal distances apart. Each ofthe said screws has a tapering pivot, b, to enter and automatically fitclosely one of three steps, 0 c c, projecting upward from the head I ofa tripod. The head I has three leg-supporting flanges, (1, extendingdownward from it, each entering between the two prongs of one of threelegs, K, furcated in its upper part, as represented. There is to eachleg ascrew-bolt, c, which goes through its prongsf f and the flange (Ibe tween them, and has screwed upon it a nut, g. By such means each legmay be clamped to its sustainingflange with the necessary power to causethe leg to move on the bolt with the necessary friction to keep steadythe leg and tripod-head while the instrument may be in use. Furthermore,the divided limb has each of its areal divisional marks arranged not radially, bar B when such side is against the saidmark. This enables theside of the bar, instead of its axis, to be used with the divisions ofthelimb, and taking or setting of angles with the instrument. From thedivided limb there project upward, on opposite sides of the telescope,two posts, L L, on the upper ends of which there is secured a st tionarymagnetic compasssupport-er, it consisting in a cylindrical box,

M, open at top, and having within and to fit it a magnetic compass, N,whose needle is shown at h. This compass can be revolved by hand withinits supporter; and there is fixed to and extended from the telescope andover.

the compass, as shown, an index-pointer, 'i, it being adapted so as tobe adjustable vertically. By means of the said pointer and the dividedlimb or ring is and needle of the compass, either angles or courses maybe determined by the telescope, as will be easily understood by personsacquainted with leveling-instruments, theodolites, orsurveying-compasses.

Fig.- 4 is a side view of the tripod and the limb G. Fig. 5 is a topview of the head of the tripod. Through the tripod-head, at its center,is a circular opening or hole, 0, to enable a plumb-line, when attachedto the divided limb at its center, to hang freely and vertically, inorder to centralize the instrument over and relatively to an object, asoccasion may require.

1 claim- The combination of the stationary magnetic compass supportingbox and the magnetic compass provided with the needle and divided limb,as set forth, with the telescope and the index-pointer applied thereto,all being adapted and arranged substantially and to opcrate asrepresented.

J OHN WARREN HARMON.

W'itnesses:

R. H. EDDY, E. B. PRATT.

but so as to line with one side of the 5

